1. Field of the Invention
The present invention relates generally to hand held remote control devices and specifically to devices that include transmitters that may be operated in connection with security alarms and systems for remotely arming and disarming a controlled security device such as a vehicle alarm.
The invention more specifically involves the use of a highly miniaturized transmitter circuit which may be contained within a housing which forms a part of a key such as an ignition key suitable for operating the vehicle in which the alarm with which the present invention may be used is located. The housing, which is mechanically connected to the key blank, also provides for an electrical connection between the transmitter circuit and the key blank so that the latter acts as an antenna for the former.
2. Prior Art
Miniaturized remote control transmitters for car alarms and other security devices are well known in the art. Typically, such devices require the use of an externally positioned antenna in order to transmit adequate power at the selected frequency of operation to permit arming and disarming of the alarm or other security system from a reasonable distance. The prior art has disclosed various techniques for implementing such an antenna, including by way of example, the use of the human body grasping the remote control transmitter as an antenna. Other examples include using the metal case of the transmitter as the antenna or providing a separate distinct antenna which may be positioned by the user such as in the form of a loop around the user's neck. More specifically, the following issued U.S. patents illustrate the known state of the art relevant to the present invention:
U.S. Pat. No. 4,725,827 to Gallegos, Jr. et al, is directed to a hand held remote control device applicable for use with security alarms. The transmitter includes a circuit board on which there is formed an open loop antenna which is coupled to a key ring, which is shown having a key suspended therefrom.
U.S. Pat. No. 3,825,833 to Bogue et al, is directed to a personal security device comprising a self-powered transmitter concealed within a device such as a hotel key. The transmitter is disposed within the key tag having a chain link for coupling to a key. However, the antenna overlays the transmitter and is not coupled to the key.
U.S. Pat. No. 4,742,336 to Hall et al, is directed to a portable intrusion detection warning system housed in a briefcase configured housing. The system includes a key which is insertable within the momentary key switch. However, the momentary key switch defines a means for disarming the electronic controller, as opposed to providing an antenna coupling to the key.
U.S. Pat. No. 3,902,118 to Ikrath et al, is directed to a body-coupled portable transmitter. The transmitter includes an external coil intended to encompass a portion of the body and couple RF energy thereto. In this way, the body becomes the antenna for radiating the transmitted signal.
U.S. Pat. No. 4,162,449 to Bouyssounouse et al, is directed to a communications system including a portable transceiver alarm unit. The portable alarm unit includes an antenna which is looped around the neck of the individual, thereby coupling to the user's body.
U.S. Pat. No. 3,134,075 to Langevin, is directed to hand-held microphone transmitter. The transmitter is housed within a metal case and includes a quarter wave antenna. The transmitter tank circuit is coupled to the metal case through a capacitor such that the user's body becomes a ground plane when the metal case is grasped, thereby making the system a better radiator.
Unfortunately, all of the remote control security system transmitting devices known to the applicant incur a certain degree of inconvenience on the part of the user. More specifically, in each such case, the user is required to carry something extra, namely, the transmitter device. Even in those cases of the prior art wherein the transmitter is implemented in a sufficiently small package to be added to a keychain or the like, some additional bulk is still required to be carried in a user's pocket or purse. Thus, in addition to the usual contents of a user's pocket or purse, consisting for example of coins, comb, lighter, wallet and, of course, keys; the additional burden and inconvenience of a remote control transmitter housing is also required in order to operate remote control security systems of the prior art.
There has therefore been a long felt need for a remote control transmitter device of the type that may be used for arming and disarming car alarms which overcomes the aforementioned principal deficiency of the prior art by providing a means for housing a remote control car alarm transmitter device in a package configuration which does not add to the bulk of materials carried in the pocket or purse of the user.